Flask 使用小结【Updating】
1、最简单的hello world
#!/usr/bin/env python
# encoding: utf-8
from flask import Flask
app = Flask(__name__)
@app.route('/')
def index():
return 'hello world'
if __name__ == '__main__':
app.run(debug=True)
#app.run(host='127.0.0.1', port=8000) 之后，访问http://localhost:5000
2、支持post/get提交
@app.route('/', methods=['GET', 'POST'])
多个url指向
@app.route('/')@app.route('/index')
不管post/get使用统一的接收
from flask import request
args = request.args if request.method == 'GET' else request.form
a = args.get('a', 'default')
3、使用url中的参数
@app.route('/query/<qid>/')
def query(qid):
pass
4、在request开始结束dosomething
一般可以处理数据库连接等等
from flask import g
app = .....
@app.before_request
def before_request():
g.session = create_session()
@app.teardown_request
def teardown_request(exception):
g.session.close()
注册Jinja2模板中使用的过滤器
@app.template_filter('reverse')
def reverse_filter(s):
return s[::-1] 或者
def reverse_filter(s):
return s[::-1]
app.jinja_env.filters['reverse'] = reverse_filter 可以这么用
def a():...
def b():...
FIL = {'a': a, 'b':b}
app.jinja_env.filters.update(FIL)
注册Jinja2模板中使用的全局变量
JINJA2_GLOBALS = {'MEDIA_PREFIX': '/media/'}
app.jinja_env.globals.update(JINJA2_GLOBALS)
5、定义应用使用的template和static目录、使用Blueprint
app = Flask(__name__, template_folder=settings.TEMPLATE_FOLDER, static_folder = settings.STATIC_PATH)
使用Blueprint
from flask import Blueprint
bp_test = Blueprint('test', __name__)
#bp_test = Blueprint('test', __name__, url_prefix='/abc')
@bp_test.route('/')
--------
from xxx import bp_test
app = Flask(__name__)
app.register_blueprint(bp_test)
6、使用session
包装cookie实现的，没有session id
app.secret_key = 'PS#yio`%_!((f_or(%)))s'
然后
from flask import session
session['somekey'] = 1
session.pop('logged_in', None)
session.clear()
#过期时间,通过cookie实现的
from datetime import timedelta
session.permanent = True
app.permanent_session_lifetime = timedelta(minutes=5)
7、反向路由
from flask import url_for, render_template
@app.route("/")
def home():
login_uri = url_for("login", next=url_for("home"))
return render_template("home.html", **locals())
8、上传文件
<form action="/image/upload/" method="post" enctype="multipart/form-data">
<input type="file" name="upload" />
接收
f = request.files.get('upload')
img_data = f.read()
直接返回某个文件
return send_file(settings.TEMPLATE_FOLDER + 'tweet/tweet_list.html')
9、请求重定向
文档：http://flask.pocoo.org/docs/api/#flask.redirect
flask.redirect(location, code=302) the redirect status code. defaults to 302.Supported codes are 301, 302, 303, 305, and 307. 300 is not supported.
@app.route('/')
def hello():
return redirect(url_for('foo'))
@app.route('/foo')
def foo():
return'Hello Foo!'
from flask import abort
@app.route('/*')
def page404():
abort(404)
@app.errorhandler(404)
def page_not_found(e):
print request.url + "\t404..."
return render_template('page404.html'), 404
获取用户真实ip
从request.headers获取
real_ip = request.headers.get('X-Real-Ip', request.remote_addr)
或者, 使用werkzeug的middleware 文档
from werkzeug.contrib.fixers import ProxyFix
app.wsgi_app = ProxyFix(app.wsgi_app)
10、Form 表单 post 数据
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import sys
reload(sys)
sys.setdefaultencoding('utf-8')
from commonFunc import *
from flask import Flask, request, redirect, url_for
app = Flask(__name__)
@app.route('/')
def index():
return redirect(url_for('username'), code=302) # URL跳转，默认代码是302，可以省略
@app.route('/username', methods=['GET', 'POST'])
def username():
HTML = '''<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8"/>
<title>Flask POST方法演示</title>
</head>
<body>
{}
<form action="" method="POST">
<textarea name="username" rows="30" cols="150"></textarea>
<br>
<input type="submit" name="enter" value="enter"
style="width:60px;height:30px; font-size:14px; color:red;"
/>
</form>
</body>
</html>'''
if request.method == 'GET':
return HTML.format('')
elif request.method == 'POST':
if request.form['username']:
urlList = request.form['username'].splitlines()
resultStr = ""
for url in urlList:
resultStr += chkListPageContent(url, getUrlContent(url), "script") + "<br>"
return HTML.format('<p>检查结果<br><strong>{}</strong></p>'.format(resultStr))
else:
return redirect(url_for('username'))
if __name__ == '__main__':
app.run(debug=True, host='127.0.0.1', port=8080)
11、处理json请求、return json & jsonp
request的header中
"Content-Type": "application/json"
处理时:
data = request.get_json(silent=False)
import json
from flask import jsonify, Response, json
data = [] # or others
return jsonify(ok=True, data=data)
jsonp_callback = request.args.get('callback', '')
if jsonp_callback:
return Response(
"%s(%s);" % (jsonp_callback, json.dumps({'ok': True, 'data':data})),
mimetype="text/javascript"
)
return ok_jsonify(data)
12、获取post提交中的checkbox
{%for page in pages %}
<tr><td><input type=checkbox name=do_delete value="{{ page['id'] }}"></td><td>
{%endfor%}
page_ids = request.form.getlist("do_delete")
13、配置读取方法
# create our little application :)
app = Flask(__name__)
# Load default config and override config from an environment variable
app.config.update(dict(
DATABASE='/tmp/flaskr.db',
DEBUG=True,
SECRET_KEY='development key',
USERNAME='admin',
PASSWORD='default'
))
app.config.from_envvar('FLASKR_SETTINGS', silent=True)
------------------
# configuration
DATABASE = '/tmp/minitwit.db'
PER_PAGE = 30
DEBUG = True
SECRET_KEY = 'development key'
# create our little application :)
app = Flask(__name__)
app.config.from_object(__name__)
app.config.from_envvar('MINITWIT_SETTINGS', silent=True)
14、几个不常用的方法：401 重定向
from flask import abort, flash
abort
if not session.get('logged_in'):
abort(401)
flash
flash('New entry was successfully posted')
Flask中实现域名301重定向
当然，这是一种非常不明智的做法，只是一种临时性的手段。301重定向应该由服务器层面的应用程序（比如NGINX，APACHE，IIS等）来完成。
代码示例如下：
def RedirectMiddleWare(request):
url = None
domain = 'www.digwtx.com'
try:
host, port = request.host.split(':')
path = request.path
except:
host = request.host
port = 80
path = request.path
if host != domain:
print 'do 301'
if port == 80:
url = 'http://%s%s' % (domain, path)
else:
url = 'http://%s:%s%s' % (domain, port, path)
return url
15、异步调用
想在flask的一个请求中处理异步, 除了使用消息系统, 可以用简单的线程处理
from threading import Thread
def async(f):
def wrapper(*args, **kwargs):
thr = Thread(target=f, args=args, kwargs=kwargs)
thr.start()
return wrapper
@async
def dosomething(call_args):
print call_args
in a request handler, call `dosomething`
16、项目配置
1.直接
app.config['HOST']='xxx.a.com'
print app.config.get('HOST')
2.环境变量
export MyAppConfig=/path/to/settings.cfg
app.config.from_envvar('MyAppConfig')
3.对象
class Config(object):
DEBUG = False
TESTING = False
DATABASE_URI = 'sqlite://:memory:'
class ProductionConfig(Config):
DATABASE_URI = 'mysql://user@localhost/foo'
app.config.from_object(ProductionConfig)
print app.config.get('DATABASE_URI') # mysql://user@localhost/foo
4.文件
# default_config.py
HOST = 'localhost'
PORT = 5000
DEBUG = True
app.config.from_pyfile('default_config.py')
17、EG. 一个create_app方法
from flask import Flask, g
def create_app(debug=settings.DEBUG):
app = Flask(__name__,
template_folder=settings.TEMPLATE_FOLDER,
static_folder=settings.STATIC_FOLDER)
app.register_blueprint(bp_test)
app.jinja_env.globals.update(JINJA2_GLOBALS)
app.jinja_env.filters.update(JINJA2_FILTERS)
app.secret_key = 'PO+_)(*&678OUIJKKO#%_!(((%)))'
@app.before_request
def before_request():
g.xxx = ... #do some thing
@app.teardown_request
def teardown_request(exception):
g.xxx = ... #do some thing
return app
app = create_app(settings.DEBUG)
host=settings.SERVER_IP
port=settings.SERVER_PORT
app.run(host=host, port=port)
18、IE 访问Flask自带服务器假死问题解决方法
threaded 多线程支持，默认不开启
processes 进程数量，默认为1个
if __name__ == '__main__':
#app.run(host='localhost', port=8080, debug=True)
app.run(host='localhost', port=8080, threaded=True, debug=True)
app.run(processes=10) 如果使用了Flask-Script来部署应用，可以给runserver命令加上--threaded参数或者--processes N参数（参数意义同上）。例如：
python manage.py runserver --threaded
或者：
python manage.py runserver --processes 3
19、Flask生成SECRET_KEY（密钥）的一种简单方法
>>> import os >>> os.urandom(24) '\xca\x0c\x86\x04\x98@\x02b\x1b7\x8c\x88]\x1b\xd7"+\xe6px@\xc3#\\' 然后： app = Flask(__name__) app.config['SECRET_KEY'] = '\xca\x0c\x86\x04\x98@\x02b\x1b7\x8c\x88]\x1b\xd7"+\xe6px@\xc3#\\' # or app.secret_key = '\xca\x0c\x86\x04\x98@\x02b\x1b7\x8c\x88]\x1b\xd7"+\xe6px@\xc3#\\' # or app.config.update(SECRET_KEY='\xca\x0c\x86\x04\x98@\x02b\x1b7\x8c\x88]\x1b\xd7"+\xe6px@\xc3#\\')
20、Flask加盐密码生成和验证函数
>>> from werkzeug.security import generate_password_hash
>>> print generate_password_hash('123456')
'pbkdf2:sha1:1000$X97hPa3g$252c0cca000c3674b8ef7a2b8ecd409695aac370'
>>> from werkzeug.security import check_password_hash
>>> pwhash = 'pbkdf2:sha1:1000$X97hPa3g$252c0cca000c3674b8ef7a2b8ecd409695aac370'
>>> print check_password_hash(pwhash, '123456')
True
21、Refer：
1、FLASK使用小结 http://wklken.me/posts/2013/09/09/python-framework-flask.html
2、Flask POST方法
http://www.itwhy.org/%E8%BD%AF%E4%BB%B6%E5%B7%A5%E7%A8%8B/python/flask-post%E6%96%B9%E6%B3%95.html
3、Day 3: Flask —— 使用Python和OpenShift进行即时Web开发
http://segmentfault.com/a/1190000000351512
4、Flask Web Development —— 模板（中）
http://segmentfault.com/blog/young_ipython/1190000000755204
5、Flask技巧
http://flask123.sinaapp.com/category/flask-tips/